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Monday, May 9, 2011

Brookings on the privacy-security compromise

This write-up is really about technology, but it goes on at length about TSA scanners. Here's the relevant excerpt:

The paradigmatic case of the kind of political mobilization on behalf of constitutional values that I have in mind is presented by my second case: the choice between the naked machine and the blob machine in airport security screening. In 2002, officials at Orlando International airport first began testing the millimeter wave body scanners that are currently at the center of a national uproar. The designers of the scanners at Pacific Northwest Laboratories offered U.S. officials a choice: naked machines or blob machines? The same researchers had developed both technologies, and both were equally effective at identifying contraband. But, as their nicknames suggest, the former displays graphic images of the human body, while the latter scrambles the images into a non-humiliating blob.[10]

Since both versions of the scanners promise the same degree of security, any sane attempt to balance privacy and safety would seem to favor the blob machines over the naked machines. And that’s what European governments chose. Most European airport authorities have declined to adopt body scanners at all, because of persuasive evidence that they’re not effective at detecting low-density contraband such as the chemical powder PETN that the trouser bomber concealed in his underwear on Christmas day, 2009. But the handful of European airports that have adopted body scanners, such as Schiphol airport in Amsterdam, have opted for a version of the blob machine. This is in part due to the efforts of European privacy commissioners, such as Germany’s Peter Schaar, who have emphasized the importance of designing body scanners in ways that protect privacy.

The U.S. Department of Homeland Security made a very different choice. It deployed the naked body scanners without any opportunity for public comment—then appeared surprised by the backlash. Remarkably, however, the backlash was effective. After a nationwide protest inspired by the Patrick Henry of the anti-Naked Machines movement, a traveler who memorably exclaimed “Don’t Touch my Junk,” President Obama called on the TSA to go back to the drawing board. And a few months after authorizing the intrusive pat downs, in February 2011, the TSA announced that it would begin testing, on a pilot basis, versions of the very same blob machines that the agency had rejected nearly a decade earlier. According to the latest version, to be tested in Las Vegas and Washington, D.C, the TSA will install software filters on its body scanner machines that detects potential threat items and indicates their location on a generic, blob like outline of each passenger that will appear on a monitor attached to the machine. Passengers without suspicious items will be cleared as “OK,” those with suspicious items will be taken aside for additional screening. The remote rooms in which TSA agents view images of the naked body will be eliminated. According to news reports, TSA began testing the filtering software in the fall of 2010 – precisely when the protests against the naked machines went viral. If the filtering software is implemented across the country, converting naked machines into blob machines, the political victory for privacy will be striking.

Of course, it’s possible that courts might strike down the naked machines as unreasonable and unconstitutional, even without the political protests. In a 1983 opinion upholding searches by drug-sniffing dogs, Justice Sandra Day O’Connor recognized that a search is most likely to be considered constitutionally reasonable if it is very effective at discovering contraband without revealing innocent but embarrassing information.[11] The backscatter machines seem, under O'Connor's view, to be the antithesis of a reasonable search: They reveal a great deal of innocent but embarrassing information and are remarkably ineffective at revealing low-density contraband.

It’s true that the government gets great deference in airports and at the borders, where routine border searches don’t require heightened suspicion. But the Court has held that non-routine border searches, such as body cavity or strip searches, do require a degree of individual suspicion. And although the Supreme Court hasn't evaluated airport screening technology, lower courts have emphasized, as the U.S. Court of Appeals for the 9th Circuit ruled in 2007, that "a particular airport security screening search is constitutionally reasonable provided that it 'is no more extensive nor intensive than necessary, in the light of current technology, to detect the presence of weapons or explosives.'"[12]

It’s arguable that since the naked machines are neither effective nor minimally intrusive – that is, because they might be designed with blob machine like filters that promise just as much security while also protecting privacy – that courts might strike them down. As a practical matter, however, both lower courts and the Supreme Court seem far more likely to strike down strip searches that have inspired widespread public opposition – such as the strip search of a high school girl wrongly accused of carrying drugs, which the Supreme Court invalidated by a vote of 8-1,[13] then they are of searches that, despite the protests of a mobilized minority, the majority of the public appears to accept.

The tentative victory of the blob machines over the naked machines, if it materializes, provides a model for successful attempts to balance privacy and security: government can be pressured into striking a reasonable balance between privacy and security by a mobilized minority of the public when the privacy costs of a particular technology are dramatic, visible, widely distributed, and people experience the invasions personally as a kind of loss of control over the conditions of their own exposure.

Needless to say, I disagree that there is any great victory over the TSA using the "blob" model. Rights are rights. The offensiveness of the naked scanner just made it an easier target for anger, but I still won't fly!